HYDROGEOLOGY AT THE FORMER NAVAL ORDNANCE STATION LOUISVILLE, LOUISVILLE, KY

Much has been written about the alluvial, Quaternary aquifer associated with the Ohio River in Louisville, Kentucky. This aquifer is the dominant hydrologic feature in the Louisville area. As part of a RCRA facility investigation associated with the privatization of the Naval Ordnance Station Louisville, the hydrogeology and extent of groundwater contamination of the overburden, shale, and limestone water-bearing zones beneath the site were characterized. Limited information on these units was readily available prior to the investigation since they are relatively insignificant from a water supply perspective. Hydrogeologic investigations were performed concurrently by Navy consultants and the USGS and included installation of over 100 monitoring wells on the nearly 150-acre property, water level measurements over 4 years, aquifer tests, including slug tests and packer tests to determine hydraulic conductivity, and colloidal borescope measurements to determine flow direction and velocity. Downhole and surface geophysical techniques were also performed, and wells were sampled and analyzed for many constituents, including natural geochemical parameters, typical groundwater contaminants, and tritium. Petroleum fingerprinting and analysis of parameters associated with natural attenuation of groundwater contamination were also performed. The results of the investigation yielded a comprehensive understanding of the hydrogeology of these units beneath the site and it’s environs. In addition, the existence of naturally-occurring petroleum was confirmed in the area, and the fate of environmental contamination in the overburden water-bearing zone beneath the site was established.